A laser processing method has been known that emits laser light to an object to be processed including a silicon substrate formed with a plurality of functional devices on a front surface in a matrix, with a back surface of a silicon substrate as a laser light entrance surface, to form a modified region near the front surface of the silicon substrate along a line to cut set in a grid pattern to pass between adjacent functional devices, and then polishes the back surface of the silicon substrate such that the silicon substrate has a predetermined thickness, to cut the object to be processed for each functional device (for example, see Patent Literature 1).